1. Field of Invention
The present invention relates to an apparatus and a method for adjusting an image. More particularly, the present invention relates to an apparatus and a method for adjusting an image for a projection display.
2. Description of Related Art
With the great improvement of computer performance and the high development of the Internet and multimedia technology, at present, image information is mostly transferred by means of digital transmission instead of analog transmission. In order to fit the style of modern life, the volumes of video or image apparatuses are gradually becoming light and thin. Conventional cathode ray tube (CRT) displays have the shortcomings of being bulky, occupying more space, and being harmful to the eyes due to radiant rays when outputting images, though they are cheap.
Therefore, recently developed flat panel displays (FPDs), such as liquid crystal displays (LCDs), organic light-emitting diode displays (OLEDs), projection displays, digital light processing (DLP) displays, liquid crystal on silicon (LCOS) displays, or plasma display panels (PDPs), have gradually become predominant in display products.
However, images displayed on displays are quite important for users in spite of the development and progress of displays. Therefore, image adjustment technology for displays is always important not only for conventional cathode ray tube (CRT) displays, but also for a series of developing flat display panels.
FIG. 1 is a schematic view of the image distortion of a conventional display. With reference to FIG. 1, an image is displayed in the display 101 after a horizontal image signal and a vertical image signal are received and integrated in the display 101. However, not all images displayed in the display 101 are perfect, because the images may be bent, distorted, and so on. Therefore, multiple sets of adjustment parameters are built in the conventional display 101 for enabling users to manually adjust the images of the display, thereby displaying desired images for users.
Multiple sets of built-in amendment parameters include a horizontal geometry correction wave 103 and a vertical geometry correction wave 105. The horizontal geometry correction wave 103 comprises multiple sets of horizontal image adjusting types 103a-103g and the vertical geometry correction wave 105 also comprises multiple sets of vertical image adjusting types 105a-105g. 
An image adjustment method for a front projection display is disclosed in U.S. Pat. No. 5,465,121. When a front projection display projects images to a non-vertical surface, the image is distorted. Therefore, an apparatus for adjusting an image distortion is developed for the front projection display. For the conventional adjustment apparatus, an image pattern for adjustment is provided as an adjustment pattern, such that a user can input the amended adjustment parameter into the adjustment apparatus according to the status of the image distortion. Then, the adjustment apparatus immediately projects the amended adjustment parameter to the non-vertical surface again as a new image, such that the user may further amend the adjustment parameter according to the result of the projection until the user is satisfied. Finally, the adjustment parameter is stored in the adjustment apparatus for facilitating a next adjustment.
However, in U.S. Pat. No. 5,465,121, only the parameter about the non-vertical projection can be adjusted. However, for the present developed ultra-thin projection displays, in view of the manufacturing of the relative elements and the manufacturing cost, the display may generate specific patterns of image distortions different from the conventional technology. The specific patterns of image distortions include multi-order curve distortions in addition to different sizes and properties of different blocks. Therefore, when a user uses the adjustment apparatus provided by the conventional technology, though an image projected to a non-vertical surface can be adjusted to have a fine adjustment effect, only the distortion caused by non-vertical projection can be adjusted, while the image distortions caused by higher-order curves cannot be adjusted.